Just like a sundial, in the two videos Curiosity shows its shadow moving on the Martian surface during a 12-hour sequence
The two black and white videos show the day of November 8th, the 4,002nd Martian day, or sunof the mission. The rover captured its own shadow moving across the surface of Mars using its own Hazard-Avoidance Camera in black and whiteor Hazcams. The instructions to record videos were part of the last set of commands sent to Curiosity shortly before the start of the Mars solar conjunction, the period when the Sun is between the Earth and . Since plasma from the Sun can interfere with radio communications, sending commands from Earth is avoided for several weeks – with the exception of regular ones for routine checks.
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Curiosity’s use of Hazcams
Those who send navigation commands to Curiosity rely on Hazcams for this locate rocks, slopes and other hazards that may be risky to cross. Since the rover’s other activities had been intentionally limited close to the conjunction, the team decided to use Hazcams to record for the first time 12 hours of stills. The goal? Catch clouds or dust devils that could reveal more about these phenomena. Unfortunately, no noteworthy phenomenon was recorded. The two videos cover a period of time ranging from 5.30am to 5.30pm local time, rgiving us the silhouette of Curiosity that moves from morning to afternoon to evening.
The video from the front Hazcam
The first video, composed of images of Front hazcamresumes the part southeast long Gediz Vallisa valley located on Mount Sharp. Curiosity has been climbing the base of the 5-kilometer-high mountain, located in Gale Crater, since 2014. At dawn, the shadow of 2 meter robotic arm of the rover moves to the left and the front wheels of Curiosity emerge from the darkness on both sides of the frame. On the left you can also see a calibration target circular mounted on the shoulder of the robotic arm. Engineers use it to test the accuracy of the X-ray spectrometeran instrument capable of detecting chemical elements on the surface. In the middle of the day, lThe front Hazcam’s automatic exposure algorithm stabilizes at exposure times of around a third of a second. At night the exposure time increases to more than a minute, and is the cause of the typical sensor noise known as “hot pixels” which appears like white snow on the final image.
The rear Hazcam video
The second video shows the rear Hazcam view while looking at nord-ovest along the slopes of Mount Sharp to the floor of Gale Crater. The rover’s right rear wheel is visible, along with the shadow of Curiosity’s power system. The small black artifact that appears on the left in the middle of the video, during the 17th frame, is the result of a cosmic ray that hits the camera sensor. Likewise, the flashing lights and other noises at the end of the video are the result of heat from the spacecraft’s power system hitting the Hazcam’s image sensor. These images have been reprocessed to correct for the wide-angle lenses of the Hazcams. The white dots visible from the images, particularly noticeable in the rear camera video, are due to 11 years of Martian dust deposited on the lenses.
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